How popular is this Philadelphia to Boulder flight route?

This flight path from Philadelphia to Boulder was viewed by 148 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

What are the cheapest airlines to fly from Philadelphia to Boulder one-way?

For one-way options, check prices for Frontier. According to our data, you can fly for as low as $64. Users have also found prices from $79 and $109 on JetBlue and American Airlines, respectively.

Weekly flight availability from Philadelphia to Boulder

The most flights from PHL to BD9 are scheduled on a Friday (16 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (3 on average).

In terms of precipitation, rainfall in Boulder ranges from 0.5 - 2.3 inches per month. May is typically the wettest month, when rainfall can reach 2.3 in. January is typically the driest time to visit Boulder when rainfall is around 0.5 in.

If weather is an important factor for your trip to Boulder, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 30.2 F).

What are the cheapest flights from Philadelphia to Boulder?

On average you can expect to pay $1,003 for a flight from Philadelphia to Boulder. The cheapest flight overall is $158 while the most popular route, (Philadelphia - Denver Intl) is currently priced at $205.

What are the most reliable airlines from Philadelphia to Boulder?

The top 3 most reliable airlines when flying from Philadelphia to Boulder are United Airlines (75%), Volaris (74%) and Air Canada (72%).

What are the most popular airlines that fly from Philadelphia to Boulder?

The most popular airlines flying from Philadelphia to Boulder are American Airlines, Frontier and United Airlines. Something to consider prior to booking your flight.

What airport do you fly from for flights from Philadelphia to Boulder?

If you book a flight to Boulder from Philadelphia, you will be flying from Philadelphia, which is the city’s only airport. Philadelphia (PHL) is located 7.0 mi from the center of Philadelphia. There are 9 flights from Philadelphia to Boulder per day from 6 different airlines.

Can I find deals for flights from Philadelphia to Boulder that include hotel bookings?

Yes. In addition to deals on Philadelphia to Boulder flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from Philadelphia to Boulder?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Philadelphia to Boulder.

Can I find deals for business class flights from Philadelphia to Boulder?

Yes. Cheapflights offers flight deals from Philadelphia to Boulder by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

Find Cheap Flights from Philadelphia to Boulder

Home Search by date Vacation packages Hotels Flight deals Car rental Travel tips & news

Find cheap flights from Philadelphia to Boulder with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheapflights Tip: The best prices from Philadelphia to Boulder are usually found in January or February, booked 31 days in advance, depart on a Saturday or Friday and return on a Thursday

Find flight deals from Philadelphia to Boulder

Most accurate provider	FlightHub 3 stars
Most trusted provider	FlightHub 3 stars
Popular in	June
Cheapest in	January
Average price	$415

Provider with most accurate pricing for Philadelphia-Denver Intl flight deals.

Search Deals

Provider most trusted by Cheapflights users for Philadelphia-Denver Intl flights.

Search Deals

Highest demand for flights based on searches. 5% potential increase in price ($21 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 2% potential price decrease ($9 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in October 2026

Search Deals

Cheapflights Insights

Everything you need to know about your flight from Philadelphia to Boulder

Prices

Airlines

What is the cheapest time of day to fly from PHL to BD9?

Unlike in the afternoon, when flights are generally more expensive, you can save up to 39% on flights from Philadelphia to Boulder by exploring options for tickets in the evening.

What is the cheapest day to fly from Philadelphia to Boulder?

Travelers seeking maximum savings on their Philadelphia to Boulder flight should consider departing on Tuesday evenings when fares are most often at their lowest. Sunday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

Reviews of airlines servicing Boulder

Read through reviews of airlines operating flights from Philadelphia to Boulder, such as Southwest,United Airlines, andJetBlue. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.

Southwest

7.9

Good

4,212 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Southwest

7.9

Good

4,212 reviews

Southwest

7.9

Good

4,212 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

United Airlines

7.4

Good

10,283 reviews

Southwest

7.9

Good

4,212 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

JetBlue

7.1

Good

3,040 reviews

Southwest

7.9

Good

4,212 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

American Airlines

7.0

Good

12,126 reviews

Southwest

7.9

Good

4,212 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Frontier

5.5

Fair

2,552 reviews

Southwest

7.9

Good

4,212 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Related info for your journey

What airport do you fly from for flights from Philadelphia to Boulder?
If you book a flight to Boulder from Philadelphia, you will be flying from Philadelphia, which is the city’s only airport. Philadelphia (PHL) is located 7.0 mi from the center of Philadelphia. There are 9 flights from Philadelphia to Boulder per day from 6 different airlines.
How popular is this Philadelphia to Boulder flight route?
This flight path from Philadelphia to Boulder was viewed by 148 users in the past month. Keep an eye out for changes in search interest prior to high and low season.
What are the cheapest airlines to fly from Philadelphia to Boulder one-way?
For one-way options, check prices for Frontier. According to our data, you can fly for as low as $64. Users have also found prices from $79 and $109 on JetBlue and American Airlines, respectively.
What are the most reliable airlines from Philadelphia to Boulder?
The top 3 most reliable airlines when flying from Philadelphia to Boulder are United Airlines (75%), Volaris (74%) and Air Canada (72%).
What are the cheapest flights from Philadelphia to Boulder?
On average you can expect to pay $1,003 for a flight from Philadelphia to Boulder. The cheapest flight overall is $158 while the most popular route, (Philadelphia - Denver Intl) is currently priced at $205.
Can I find deals for flights from Philadelphia to Boulder that include hotel bookings?
Yes. In addition to deals on Philadelphia to Boulder flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Philadelphia to Boulder?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Philadelphia to Boulder.
Can I find deals for business class flights from Philadelphia to Boulder?
Yes. Cheapflights offers flight deals from Philadelphia to Boulder by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Alternative routes

Complete your trip

Flights by cabin class

Other flight options

Other flights from Philadelphia

Popular flights

Top destinations

Alternative routes for Philadelphia to Boulder

Newark to Denver flights

John F Kennedy Intl to Denver flights

LaGuardia to Denver flights

Dulles Intl to Denver flights

Philadelphia to Denver flights

Reagan-National to Denver flights

Pittsburgh to Denver flights

Newark to Vail flights

Newark to Hayden flights

John F Kennedy Intl to Vail flights

Harrisburg to Denver flights

Newark to Montrose flights

LaGuardia to Vail flights

LaGuardia to Hayden flights

Dulles Intl to Vail flights

John F Kennedy Intl to Aspen flights

Allentown to Denver flights

LaGuardia to Montrose flights

Newark to Aspen flights

Dulles Intl to Colorado Springs flights

Newark to Colorado Springs flights

John F Kennedy Intl to Colorado Springs flights

Scranton to Denver flights

Philadelphia to Colorado Springs flights

LaGuardia to Colorado Springs flights

Reagan-National to Colorado Springs flights

Dulles Intl to Hayden flights

Dulles Intl to Aspen flights

Dulles Intl to Grand Junction flights

Newark to Grand Junction flights

State College to Denver flights

Pittsburgh to Colorado Springs flights

Newark to Durango flights

Philadelphia to Aspen flights

Philadelphia to Grand Junction flights

Pittsburgh to Grand Junction flights

Top 6 airlines flying from Philadelphia to Boulder

Airline	Cheapest	Average	Flexibility	On-time
Frontier	Cheapest$96	Average$263	FlexibilityNo cancel fee	On-time62%
United Airlines	Cheapest$215	Average$462	FlexibilityNo cancel fee	On-time69%
JetBlue	Cheapest$220	Average$338	FlexibilityNo cancel fee	On-time62%
American Airlines	Cheapest$235	Average$453	FlexibilityNo cancel fee	On-time71%
Delta	Cheapest$236	Average$475	FlexibilityNo cancel fee	On-timeN/A
Southwest	Cheapest$258	Average$490	FlexibilityNo cancel fee	On-time63%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.

Cheap flights from Philadelphia (PHL) to Boulder, CO

Find cheap flights from Philadelphia to Boulder with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Find flight deals from Philadelphia to Boulder

Most accurate provider

Most trusted provider

Popular in

Cheapest in

Average price

Cheapflights Insights

What is the cheapest time of day to fly from PHL to BD9?

Unlike in the afternoon, when flights are generally more expensive, you can save up to 39% on flights from Philadelphia to Boulder by exploring options for tickets in the evening.

What is the cheapest day to fly from Philadelphia to Boulder?

Travelers seeking maximum savings on their Philadelphia to Boulder flight should consider departing on Tuesday evenings when fares are most often at their lowest. Sunday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

Weekly flight availability from Philadelphia to Boulder

The most flights from PHL to BD9 are scheduled on a Friday (16 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (3 on average).

Reviews of airlines servicing Boulder

Read through reviews of airlines operating flights from Philadelphia to Boulder, such as Southwest,United Airlines, andJetBlue. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.

Related info for your journey

What airport do you fly from for flights from Philadelphia to Boulder?

How popular is this Philadelphia to Boulder flight route?

What are the cheapest airlines to fly from Philadelphia to Boulder one-way?

What are the most reliable airlines from Philadelphia to Boulder?

What are the cheapest flights from Philadelphia to Boulder?

Can I find deals for flights from Philadelphia to Boulder that include hotel bookings?

How can I find direct flights from Philadelphia to Boulder?

Can I find deals for business class flights from Philadelphia to Boulder?

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Philadelphia to Boulder

See prices for flight routes from nearby airports that may be better suited for you.

Complete your trip

Complete your trip to Boulder by adding a car rental and/or hotel reservation to your travel itinerary.

Search flights from Philadelphia to Boulder by cabin class

Find flights from Philadelphia to Boulder, based on your preferred cabin class, be it economy, premium economy, business, or first class.

Philadelphia and Boulder flights

Browse other Philadelphia and Boulder flight options. Last updated on October 5, 2026.

Other flights from Philadelphia

Browse through other flights departing from Philadelphia. Flights are based on user searches made on Cheapflights and were last updated on October 5, 2026.

Popular flight searches

Check out other popular destinations found by fellow travelers in 2026

Philadelphia to Boulder flights

Consider these flights traveling from Philadelphia to Boulder.

Top 6 airlines flying from Philadelphia to Boulder

100% Free

Book with Flexibility

Travel Smart